Worried my polymer clay Masters details will break off in silicone mold

I am making a sculpture out of polymer clay of a human heart. I am adding a lot of veins on the outside that are a bit delicate in texture. The main part of the heart has already been baked and the veins aren't sticking that well so I've been having to super glue them when raw. After the final baking I have broken off 1 vein that I was able to glue back on. I am planning on doing a two-part silicone mold that I will then cast in resin for a second master(I'm paranoid when I pour the silicone into the silicone mold I might screw something up), then in silicone. I am concerned that after I pour the silicone the fine veins will break off being left behind in the silicone cast. My thought was sealing around the edges of the veins with something like an acrylic sealer but I'm not sure if that will even be effective. My plan is to paint the heart afterwards so find details of the surface of the heart will probably be covered up if there are spots that end up glossy. Does anyone have suggestions for keeping the veins in place when I pull out the master? Is an acrylic sealer a good idea or should I keep with the super glue and just run a line around where the veins meet the heart skin? I'd really rather not have to pick out tiny veins from my silicone mold.